Wen Zheyu, Liu Qizhen, Yu Chao, Huang Lukuan, Liu Yaru, Xu Shun'an, Li Zhesi, Liu Chanjuan, Feng Ying
MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Livestock Industrial Development Center of Shengzhou, Shaoxing 312400, China.
Toxics. 2023 Apr 13;11(4):371. doi: 10.3390/toxics11040371.
Chromium (Cr) is a major pollutant affecting the environment and human health and microbial remediation is considered to be the most promising technology for the restoration of the heavily metal-polluted soil. However, the difference between rhizosphere and endophytic bacteria on the potential of crop safety production in Cr-contaminated farmland is not clearly elucidated. Therefore, eight Cr-tolerant endophytic strains of three species: (SR-12), (LB-15) and (PA-1) were isolated from rice and maize. Additionally, one Cr-tolerant strain of (AF-1) was isolated from the rhizosphere of maize. A randomized group pot experiment with heavily Cr-contaminated (a total Cr concentration of 1020.18 mg kg) paddy clay soil was conducted and the effects of different bacteria on plant growth, absorption and accumulation of Cr in lettuce ( var. Hort) were compared. The results show that: (i) the addition of SR-2, PA-1 and LB-5 could promote the accumulation of plant fresh weight by 10.3%, 13.5% and 14.2%, respectively; (ii) most of the bacteria could significantly increase the activities of rhizosphere soil catalase and sucrase, among which LB-1 promotes catalase activity by 224.60% and PA-1 increases sucrase activity by 247%; (iii) AF-1, SR-1, LB-1, SR-2, LB-2, LB-3, LB-4 and LB-5 strains could significantly decrease shoot the Cr concentration by 19.2-83.6%. The results reveal that Cr-tolerant bacteria have good potential to reduce shoot Cr concentration at the heavily contaminated soil and endophytic bacteria have the same or even better effects than rhizosphere bacteria; this suggests that bacteria in plants are more ecological friendly than bacteria in soil, thus aiming to safely produce crops in Cr-polluted farmland and alleviate Cr contamination from the food chain.
铬（Cr）是一种影响环境和人类健康的主要污染物，微生物修复被认为是修复重金属污染土壤最具前景的技术。然而，根际细菌和内生细菌对铬污染农田作物安全生产潜力的差异尚未明确阐明。因此，从水稻和玉米中分离出了三种共8株耐铬内生菌株：（SR-12）、（LB-15）和（PA-1）。此外，从玉米根际分离出1株耐铬菌株（AF-1）。进行了一项随机分组盆栽试验，使用铬重度污染（总铬浓度为1020.18 mg/kg）的稻田黏土，比较了不同细菌对生菜（变种Hort）生长、铬吸收和积累的影响。结果表明：（i）添加SR-2、PA-1和LB-5可分别使植物鲜重积累提高10.3%、13.5%和14.2%；（ii）大多数细菌可显著提高根际土壤过氧化氢酶和蔗糖酶活性，其中LB-1使过氧化氢酶活性提高224.60%，PA-1使蔗糖酶活性提高247%；（iii）AF-1、SR-1、LB-1、SR-2、LB-2、LB-3、LB-4和LB-5菌株可显著降低地上部铬浓度19.2% - 83.6%。结果表明，耐铬细菌在重度污染土壤中具有降低地上部铬浓度的良好潜力，且内生细菌的效果与根际细菌相同甚至更好；这表明植物中的细菌比土壤中的细菌更具生态友好性，从而旨在实现铬污染农田的作物安全生产并减轻食物链中的铬污染。
